Pavlov's conditioning works by using controlled and uncontrolled stimulus to get the desired reaction. In his experiment, Ivan Pavlov used a bell and paired it with food to condition the dog to drool every time it hears the bell because it has associated the sound with food. It's the same thing video games use to lead gamers into a certain action whether it be through positive or negative feedback.

Gamers might not have noticed it but the whole game mechanic of video games revolve around this psychological principle. For example, the Super Mario game uses this to encourage players to keep on playing by rewarding them with coins. Other games have also their own reward system where the player gets a bigger and better item as he progresses.

Game developers also use Pavlov's conditioning to limit the number of hours players use to play the games. For example, some games reward players with bonus points for every hour they are logged off from the game.

In other cases, games condition the player to return after a certain number of days to get a reward. A good example of this is 'Candy Crush' where the game stops after players reach a certain level and resumes again after a number of days. The above are examples how conditioning uses positive feedback in games.

Conditioning using negative feedback includes decreasing the character's experience level when it dies, eating some poison, or running out of lives. Where positive feedback lets the player do something, negative feedback stops the player from doing it. This usually happens to enforce the rule and mechanics of the game.

For example, some games give conditional items which the players need to manage carefully because if they don't they will die by it. That conditions the player earlier in the game to be careful or not do a certain action once again if they want to survive.

Why is there classic conditioning in a game in the first place? The answer is simple: in order for a game to exist, there should be a win and lose situation that needs to be established first. Once this is established, then the other elements and mechanics of the game follow.